Fishing while the world burns: A Fine-Tuned Critique of P.Z. Myers

Continuing my series on truly awful internet articles on the topic of the fine-tuning of the universe for life, we turn to the work of Professor PZ Myers. Myers is a biologist at University of Minnesota Morris. He is known for his work in evolutionary biology and his outspoken opposition to the Intelligent Design movement.

On November 24, 2007, Paul Davies published an OpEd piece in the New York Times entitled “Taking Science on Faith”, discussing the commonly held but rarely discussed belief among scientists that the laws of nature are dependable, immutable, absolute, universal, and mathematical. The Edge Foundation published replies from a number of scientists. I hope to be able to discuss the wonderful, thoughtful responses of Lee Smolin and Sean Carroll soon. Here I will focus on the Myers’ reply.

In his response-to-the-responses, Davies takes Myers to task for missing the whole point of his article: “Myers goes on to attribute to me precisely the point of view I am seeking to refute”. It only gets worse when the fine-tuning of the universe is raised. Here’s Myers:

Alas, Davies also brings up the anthropic principle, that tiresome exercise in metaphysical masturbation that always flounders somewhere in the repellent ditch between narcissism and solipsism. When someone says that life would not exist if the laws of physics were just a little bit different, I have to wonder … how do they know? Just as there are many different combinations of amino acids that can make any particular enzyme, why can’t there be many different combinations of physical laws that can yield life? Do the experiment of testing different universes, then come talk to me. Until then, claiming that the anthropic principle, an undefined mish-mash of untested assumptions, supports your personal interpretation of how the universe exists and came to be is a self-delusional error.

I’m also always a bit disappointed with the statements of anthropic principle proponents for another reason. If these are the best and only laws that can give rise to intelligent life in the universe, why do they do such a lousy job of it? Life is found in one thin and delicate film on one planet in this mostly empty region of space, and even if there are other fertile planets out there, they will be nearly impossibly distant, and life will be just as fragile and prone to extinction there as here. Even on this world, all of the available environments favor bacteria over scientists or theologians, and said scientists and theologians have existed for only about 0.00001% of the lifetime of this universe.

If I wanted to argue for a position on the basis of the anthropic principle, rather than trying to pretend that we live in a Goldilocks universe, we should be wondering how we ended up in such a hostile dump of a universe, one that favors endless expanses of frigid nothingness with scattered hydrogen molecules over one that has trillions of square light years of temperate lakefront property with good fishing, soft breezes, and free wireless networking.

Myers has two main arguments, expressed as rhetorical questions:

1. How do we know that life would not exist if the laws of physics were just a little bit different?

2. How can the universe be fine-tuned for life when there is so little life in the universe, and so much of the universe is hostile to life?

My response to the first question is: because we can do theoretical physics. We don’t just measure the natural world, though this is crucial part of science. We can, with exquisite accuracy, predict the behaviour of the physical world by writing things on a sheet of paper. We propose models and explore their mathematical predictions. We find that there are parameters in these models that are not determined by the theory; they need to be measured in experiments. With these parameters in hand, the theory describes our universe beautifully. It follows that if these parameters (or the laws themselves, or the initial conditions of the universe) were different, then our universe would be different. Making theoretical predictions about these other universes is exactly the same process as making predictions about this universe. Experimental confirmation of our predictions in this universe makes us confident that the theory is correct, and thus we can predict what would happen in other universes.

Thus Myers’ claim that we cannot know what would happen if the laws of physics were different boils down to the claim that we cannot do theoretical physics. We can only “do the experiment”. This is an awfully big claim, coming from a biologist. Especially an evolutionary biologist. Will Myers demand that we “do the experiment” of creating another earth and observing it for a few billion years before he believes that all life on earth evolved from chemicals via Darwinian processes? Or is he willing to extrapolate from experimentally tested scientific theory?

Myers’ question is simply an admission of his own ignorance. How do we know? The reasons are all there in Barrow and Tipler, Hogan, Rees, Carter, Carr, Ellis et al. Has Myers carefully studied the research of these physicists and found it wanting? Myers seems to be offering nothing more than an argument from personal ignorance.

Myers asks: “Why can’t there be many different combinations of physical laws that can yield life?” This is aimed at a straw man. The claim is not that ours is the only (or best) universe that could support life, or that we are the only possible form of life. The claim is that if a universe were chosen at random from the range of possible universes, the probability of that universe being able to support intelligent life is very small. This claim is entirely consistent with the existence of other possible forms of life. To counter the claim that the universe is fine-tuned for the existence of life, Myers would need to give us some reason for believing that, given almost any set of physical constants + laws of nature + initial conditions, some form of intelligent life is able to develop.

Myers’ says that anthropic claims are “an undefined mish-mash of untested assumptions”. Let’s consider an example. If the strength of the strong force were decreased by 50%, all the atoms of all the elements used by living things would disintegrate. Undefined? It’s better than defined; it’s quantitative. This is the kind of mathematical precision that causes “physics envy” amongst biologists. Mish-mash? The sheer number and variety of fine-tuning claims are strong insurance that not all of them are wrong. Untested? Only if Myers has reason to think that we don’t understand the strong force. Assumption? No, calculation. (Masturbation? No comment.)

If Myers can imagine a form of intelligent life that could exist in such a universe, then he should tell us. We have positive reasons for believing that stable, information-carrying, replicating entities are not possible in such a universe. We know what these simple elements (H, He, Li, Be, B) can do chemically, and it’s not very much. You could (andmanyhave) fill textbooks with all the chemical possibilities of carbon. You would struggle to fill a page on the chemistry of the first 5 elements of the periodic table. Carbon can make DNA. Beryllium couldn’t make a mess. Given the extraordinary complexity of life in this universe, it is reasonable to conclude that life is rather hard to please when it comes to universes and their laws.

Regarding question two: this is a complete non-sequitur. Suppose I claimed that in the space of possible arrangements of metal and plastic, the set of functioning automobiles is vanishingly small. There are many ways to make a car, but vastly more ways to make a pile of rubbish. Could this claim be refuted by complaining that my car doesn’t go very fast? Or that you think you could make a better car? Or that 99% of all the cars ever made no longer work? Or the possibility of aeroplanes? Myers apparently believes that a universe can only be fine-tuned if it is crammed full of life, from end to end and from start to finish.

Every criticism of this universe by Myers backfires. Life is delicate and fragile – precisely! The fragility of life supports the claim that life is very choosy about where it can form and live. If you understand why life cannot exist in frigid, dilute space, then you understand why life cannot exist in a universe in which the “lumpiness” parameter (Q) is 0.000001 (rather than 0.00001 in our universe), because in such a universe there is only frigid, dilute space. (If Q is 0.0001, you get frigid, dilute space interspersed with black holes). The same would be true if the density of the universe at the Planck time were reduced by 1 part in , or if the cosmological constant were larger by 1 part in of its natural range. Or if gravity were too weak to form matter into galaxies, stars, planets and people. Or if stars simply collapsed when they ran out of fuel (rather than exploding in supernovae), swallowing the elements they produced into neutron stars or black holes. I could go on.

Once again, Myers puts his ignorance on parade. We know why the universe is so large and dilute. John Barrow puts it quite nicely in his book “The World Within The World” (see also this article; John Wheeler makes exactly the same point in his outstanding “At Home in the Universe”):

A Universe that contained just one galaxy like our own Milky Way, with its 100 billion stars, each perhaps surrounded by planetary systems, might seem a reasonable economy if one were in the universal construction business. But such a universe, with more than a 100 billion fewer galaxies than our own, could have expanded for little more than a few months. It could have produced neither stars nor biological elements. It could contain no astronomers.

We know why it takes so long for life to appear in the universe – it takes billions of years for stars to form the necessary elements, and for these elements to collect into planets. It takes stars billions of years to form the elements because they are the energy source for life and thus need to be very stable. Paradoxical as it seems, endless expanses of frigid nothingness are necessary for a universe to be old enough for life to develop.

What does Myers want? To be at the centre of the universe? There isn’t one. To be at the centre of a galaxy? There’s a supermassive black hole there. To be at the centre of the solar system? It’s 10 million degrees in there. For the Earth to be larger? It would need to become a nuclear bomb (a star) to support itself against gravity. For the universe to be smaller, or less empty? It would collapse within a year.

Let’s allow Myers to create his “trillions of square light years of temperate lakefront property”. If he wants soft breezes then he’ll need gravity to hold his atmosphere together, to prevent it from dispersing. Gravity, in turn, will make this endless lake collapse (regardless of its size) in about = 1 day. So he’ll need to fish quickly, as he’ll be crushed into oblivion by about this time tomorrow. Unless the extreme heat generated in the collapse can counteract gravity, but that would probably boil the fish, ionise their remains and ignite the whole thing in a nuclear explosion. (Myers lakefront property is too massive for solid-state interatomic forces to support it against its own gravity. According to the virial theorem, it would be crushed into a sphere and heated to around ten million degrees Celsius.) Thank God Myers isn’t God. Perhaps Myers expects “someone” to suspend the laws of nature to preserve his utopia. Science would then be impossible, so it’s a bit odd that Myers would prefer this kind of universe, where rational inquiry isn’t rewarded with knowledge.

Let’s summarise: it is painfully, embarrassingly obvious that Myers has never seriously investigated the fine-tuning of the universe for life. When he isn’t aiming his riposte at a straw man, he’s passing judgment on whole of theoretical physics. He criticises features of our universe without which he would not exist and asks rhetorical questions that were answered long ago. Not content with merely demonstrating his ignorance, Myers proceeds to parade it as if it were a counterargument, allowing him to dismiss some of the finest physicists, astronomers, cosmologists and biologists of our time as “self-delusional”. When Myers can show that he has taken them seriously, we might just start to take him seriously.

27 Responses

Alas, it seems that, as a species, we are quite apt to strenuously argue for or against something that we haven’t seriously investigated. Just see Sir Arthur Conan Doyle’s Professor Challenger doing exactly this in The Land of Mist (http://gutenberg.net.au/ebooks06/0601351h.html) for example.

On the first point, no, I certainly do not dismiss the work of theoretical physicists, nor do I expect them to cobble up new physical universes to do the experiment. Theoretical calculations are just fine. I can appreciate that huge differences lead to calculably huge effects — reducing the strong force by 50%, though, is a great big turn of the knob. This is a fine-tuning claim, though, where I hear over and over again that the universal constants have to be exactly and precisely just so. How much wobble is allowable? No one seems to want to say.

On point two: I’m obviously making an exaggeration for effect, but the general point remains: how do you know there isn’t a better solution? Life is fragile and lives in only a vanishingly tiny fraction of the total volume of the universe, a point you readily concede; how do you know that there isn’t a miniscule adjustment of the physical constants that would, say, double the amount of available life-friendly real estate in the universe? We can easily see that what we have now is good enough, or we wouldn’t be here at all…but there is no evidence that this is the best of all possible universes. Remember, Goldilocks saw three bowls of porridge, one too hot, one too cold, and one just right, but she could have subsisted just fine on any one of the three. How do you know we aren’t dining on porridge that’s just a bit too cold right now?

Greeting, Prof. Myers! It’s a privilege to have you comment on our humble blog.

And, yes, 2 years is a long time on the internet …

“50% is a big turn of the knob” – that’s 50% of the strength of the strong force in our universe, which might be a tiny fraction of possible range of strong forces. I use that illustration, not because its an obviously tiny change, but because it clearly demonstrates the drastic changes that fiddling with the knobs can make.

“How much wobble is allowable?” Here’s an example:http://arxiv.org/pdf/astro-ph/9908247 . A change in the strong force of 0.4% and stars produce oxygen or carbon but not both. That may not make life impossible, but it does make it much more difficult. If the proton were heavier my 0.1%, then there were be no hydrogen in the universe, and thus no long-lived stars. I also cited the lumpiness parameter above. Martin Rees’ “Just six numbers” should be quantitative enough for you, or perhaps some shameless self-promotion: http://www.youtube.com/watch?v=XT_qDaVJ8mU

“There is no evidence that this is best of all possible universes”. Certainly you can’t use the fine-tuning to claim that this is the best possible universe, where “best” means a maximal amount of life or fish. (I’d have gone for beach-front, myself).

But we can make the lesser claim that the fine-tuning of the universe is evidence against the hypothesis: this universe is the only one, and its properties were chosen at random. The alternative hypotheses are multiple universes or non-randomly chosen properties. In short: “If you don’t want God, you’d﻿ better have a multiverse” (Bernard Carr). “If you discovered a really impressive fine-tuning … I think you’d really be left with only two explanations: a benevolent designer or a multiverse” (Steven Weinberg). That’s my point.

In short, your reply was quite good against some of the unfortunately common misconceptions of the fine-tuning of the universe. But there are more sophisticated advocates, and Davies is one of them. (I can recommend Robin Collins’ article in “The Blackwell companion to Natural Theology”). And not just theists/deists. Martin Rees, Alex Vilenkin et al. want to use fine-tuning to argue for a multiverse. I think Prof. Dawkins is drawn to that idea also.

O.4% is still a lot. 0.1% is also a lot. My point is not that physics is invalid, but that there are too many combinations for you to argue for fine tuning. What if parameter X were tweaked up by 0.0001%, and Y were turned down by 0.003%, that sort of thing.

I admit that I’m coming at it from a biological perspective. We heard similar arguments (and still do!) that, for instance, the human body was too complex and too precisely functional to have evolved. Yet when we actually get down into the details, we turn out to be very, very sloppy. Not at the level of “you can get rid of the pancreas, we’re fine”, but “look at all the isozymes produced by the pancreas, and look at all the variants incorporating deletions and duplications in the real world” (and also, “look at all these animals that have an analog to the pancreas, but not a pancreas proper”). I don’t have a good feel for the slop permitted in all these fine-tuning calculations, and proponents of fine-tuning don’t talk about them. They’re trying to make a different rhetorical point.

Your “lesser claim” is also completely unsupported. Sure, the universe could be the only one, and it could be the product of pure chance. You’ve only got an n of 1. You simply can’t make a probabilistic argument on the basis of one data point. I’ve never seen the logic of that particular argument for multiverses, either. I’ve also never seen another possibility addressed, that of necessity. Maybe all those universal constants are not independent, but coupled…and their relationships are fixed because they are only side-properties of a single initial property, which may be fixed in turn by its instantiation with universe-creation. So you can only get universes with a set of constants that are compatible with the creation of universes.

“In short: “If you don’t want God, you’d﻿ better have a multiverse” (Bernard Carr). “If you discovered a really impressive fine-tuning … I think you’d really be left with only two explanations: a benevolent designer or a multiverse” (Steven Weinberg). That’s my point.”

You forgot an important third option, that PZ also mentioned in his most recent paragraph. It could be that the constants have the values that they do for some understandable reason (isn’t that what a theory of everything is supposed to explain?), and we just don’t know that reason yet.

There are good historical precedents for this: for example, the speed of light, the permittivity of free space and the permeability of free space (ugh, I hate jargon – the strength parameters of electricity and magnetism) can not be varied arbitrarily, given any two, the third is fixed.

Ah necessity … now we’re getting somewhere. It’s one of my criticisms of William Lane Craig that, faced with necessity, his first response is: we know of know reason why the constants have the values that they do. That’s perhaps true, but not good enough – no physicist believes that we have heard the last word on what we now think are the fundamental constants.

In their classic paper on fine-tuning in 1979, Carr and Rees consider the possibility of necessity being the explanation of the fine-tuning. They comment that “it would still be remarkable that the relationships dictated by physical theory happened also to be those propitious for life.”

I’m inclined to agree. If we discovered that something like Brendon’s electromagnetism example was true for some of the the 26 or so fundamental constants, that would reduce the amount of fine tuning but not eliminate it. I don’t think you can escape the fact that there are other ways that our universe could have been, and the vast majority are not capable of supporting life.

A good test case is string theory. Suppose that, if string theory is true, all the constants of nature boil down to one super-constant, which itself just sets the scale of the universe and thus cannot be fine tuned. (Not all string theorists believe this, incidentally). Even if there are no alternatives within string theory, there are alternatives to string theory. And even if the equations of string theory contain no free parameters, “their solutions … are characterised by several hundred parameters-the sizes of compact dimensions, the locations of the branes, and so on” (Alex Vilenkin).

I’d love to hear Brendan’s response to the claim “You simply can’t make a probabilistic argument on the basis of one data point”. Bayesians disagree. My response is twofold. Probability is about what is likely from amongst what is possible, so it’s not reply to say that “we only have one actual datapoint.” Secondly, if this argument worked, it would work in any universe. It would prove “the absurdity that an infinitely powerful Creator could do nothing whatever to indicate his existence when choosing the properties of any universe he created … If the message MADE BY GOD were written everywhere thanks to the action of Nature’s forces then we shouldn’t need to travel to other universes which lacked such messages before concluding that the forces has quite probably been carefully selected, if not by God then at least some immensely powerful person.” (John Leslie).

Why does Myers get so much attention? He is an Assistant Professor at a third rate university, and devotes his “publishing” efforts to a blog known for expressing bigotry against Christians and Jews under the cover of “science”.

He gave up long ago on the idea of publishing peer reviewed science papers.

“Thus Myers’ claim that we cannot know what would happen if the laws of physics were different boils down to the claim that we cannot do theoretical physics. We can only “do the experiment”. This is an awfully big claim, coming from a biologist. Especially an evolutionary biologist. Will Myers demand that we “do the experiment” of creating another earth and observing it for a few billion years before he believes that all life on earth evolved from chemicals via Darwinian processes? Or is he willing to extrapolate from experimentally tested scientific theory?”

This is a classic creationist fallacy. The conclusion of common descent is not an extrapolation from evolution that is occurring today, but rather than conclusion of many different lines of evidence, such as nested hierarchies, the pattern of pseudogenes and endogenous retroviruses, convergence of independent phylogenies, atavisms, fossils with transitional features etc. All of this is experimentally corroborated of course and no such extrapolation is necessary.

Let us compare this with your kind of theoretical physics. If you had a model that had only been tested in, say 1/(10^500) of the range it is claimed to be applicable to and is, for all we know, fundamentally untestable in all other areas, can you honestly say that you would consider this model well-tested? Can you honestly say you would have high confidence that this model made accurate predictions in the incredibly large untested region? If anything, it appears that some theoretical physicists suffer from biology-envy. At least many biologists can test their models in the areas they claim it is accurate for, whereas the lack of testability / falsifiability has plagued some areas of modern theoretical physics. Adjusting your model to fit the facts after-the-fact does not cut it. There has to have actual predictive power, those predictions need to be tested and the conclusions have to be supported by the results.

So making predictions about other universes is not the same as making predictions about this universe. The reason is that, at least for now, you cannot test predictions about other universes. You can only say that “well, assuming those universes are accurately described by this model, then so and so is the case”. But of course, this assumption is inherently unjustified.

Nonsense.
* The hypothesis of common descent is a hypothesis about what has happened in the history of life over the last couple of billion years. There can be no *experimental* evidence for this hypothesis because its not a hypothesis about what happens in laboratories. How can you make a statement about the history of life for the last few billion years without making an extrapolation?

* This is not to say that there is no *empirical* evidence for common descent, as you listed. Before you use the C-word again, let me clarify that I am not in any way calling into question the truth of the hypothesis of common descent. Rather, my point is this: for these observations to be counted as evidence for common descent, we must be able to answer the question “if life on earth has descended from a common ancestor over the last several billion years, what would we expect to observe?”. (If you know Bayes theorem, we need the likelihood). This is an indispensable part of the scientific method, biological, physical or otherwise. What are the predictions of the model? If common descent were true, what would I expect to see (and not see) in the fossil record?

* Biologist-envy? Absolutely … when it comes to model testing. I’m an astrophysicist – the things I study are billions of light years away. I’d love to have a biologist’s data! Model formulating, on the other hand … I wouldn’t like to write down the equation for a retrovirus.

* You say: ‘You can only say that “well, assuming those universes are accurately described by this model, then so and so is the case”’. YES! YESYESYESYES! That’s all I’m trying to say! We can *formulate* models describing other ways our universe could have been, and when we do, we find that life-permitting universes are very rare in the set of possible universes. I’m not claiming anything about this universe, or any other actual existing universe. That’s why your talk of testing theories, and Prof Myers’ demand to “Do the experiment” completely misunderstands the claim being made. In the set of possible universes, the subset that permits the existence of life is very small.

* Note carefully the difference between formulating a model and testing a model. Formulating predictions about other universes is exactly the same process (in terms of writing down and solving equations) as formulating predictions about this universe. Of course, testing predictions about other possible, different universes is nonsense – they’re different universes.

There is plenty of experimental evidence for common descent. You see, the model of common decent makes bold predictions about what we should find to be the case if we study organisms in the lab, such as consilience of independent phylogenies from endogenous retroviruses, pseudogenes, biochemistry and so on. Since the predictions of common descent is confirmed the in the lab and because that model better explains the evidence than any other, we provisionally accept it as the best current description of the history of life. To be sure, there are extrapolations involved. For instance, we have not yet tested every single organism on earth, so it is conceivable that, say, all organisms but three specific lizards are related by common descent. However, this is not the kind of extrapolation that is used in certain areas of theoretical physics. There we make extrapolations into the, as far as we known, intrinsically untestable region that is, by your own admission, vastly larger than the testable regions.

As for the precise experimental predictions of common descent, Douglas Theobald was written perhaps the best outline called “29+ Evidences for Macroevolution: The Scientific Case for Common Descent”. If I may pick a few examples from it (I will return to the predictions about the fossil record below):

1. Nested hierarchies:

If common descent is correct, we should observe nested hierarchies or groups-within-groups (which we do). To take plants as an example, monocotyledons and dicotyledons are nested within the angiosperm (plants with enclosed and protected seeds) group, and the angiosperm and gymnosperms (seeds that are not enclosed) are nested in the seed plants and seed plants and non-seed plants are nested in the vascular group. The vascular group and non-vascular group is nested within plants.

Also, the standard phylogenetic tree have statistical and practically significant high values of hierarchical structure.

Now you can classify almost anything, such as cars, into hierarchies if you want, but there is no requirement for, say, a blue car to have four doors in the same way that nonvascular plants cannot have seeds or flowers. So hierarchical classifications of cars would be subjective, but that of organisms would not. Take languages as an other example. They share common ancestors and derived by the same decent with modification and can be classified in objective nested hierarchies. No reasonable person could claim that Swedish should be grouped with Mandarin rather than with Norwegian.
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On the other hand, it would have been profoundly problematic if it had turned out that many different species had combined characteristics from different nested groups. What if we found nonvascular plants with seeds? Conifers with flowers? Ferns with woody stems? Birds with mammary glands or hair? Fish with differentiated teeth? If there existed a mix and match of characters, it would make it hard to create objective nested hierarchies. In fact, this would be an eminent way to falsify common descent.

On the other hand, cars do mix and match characters, which is why they can only be subjectively grouped.

2. Consilience of independent phylogenetic trees.

If common descent is correct, we should expect that phylogenetic trees constructed from independent lines of evidence (say, genetics and morphology etc.) should seamlessly converge with a high degree of statistical and practical significance. Now, as the number of taxa analyzed increases, the number of theoretically possible trees increase very fast. There are over 10 to the power of 38 different ways to order 30 major taxa. Yet trees constructed from morphological characters are congruent with trees determined independently from e. g. molecular studies on cytochrome c.

Even partly incongruent trees match with a high degree of significance, simply by the vast number of theoretically possible trees. A very loose analogy is trying to measure a physical variable and coming up with results around, say 10 (your test series could be 9.82, 9.94, 10.04, 10.12 etc.). These are strictly speaking not the same, but it is easy to see that they center around something that is close to 10.

If it was the case that there was no consilience of independent phylogenetic trees derived from morphology and molecular data, it would have falsified common descent. Indeed, based on the extremely large number of theoretically possible trees, a lack of consilience of independent phylogenetic trees is the most likely result.

Not only that, we can now test the notion that independent phylogenetic trees are consilience by checking things like chromosome number, length and the chromosomal position of genes. These are roughly independent of morphology and DNA sequence of specific genes. If the results show that these too are consistent, then this is further evidence for common descent. If they do not, we have a problem.

3. Endogenous retroviruses

Endogenous retroviruses (ERVs) are remnants of retroviruses that have been incorporated into the genome of the infected cell and for some reason failed to complete its cycle. This can be due to mutation within the integrated viral DNA or unfavorable circumstances whatever. If this occurs in germ cells, descendants will also carry this broken retroviral integration. Now, this type of integration is uncommon and mostly random, so finding similarities of endogenous retroviruses (sequence, number, types etc.) indicate closer evolutionary relationship.

Humans and chimps share more of their ERVs that either compared to other primates. These two and gorillas share more of their ERVs compared to other primates. These three share more of their ERVs that either of them do with orangutangs, which in turn share more of their ERVs than either of them do with gibbons, which in turn share more of their ERVs than either do with old world monkeys, which together share more of their ERVs than either do with new world moneys and so on. This supports common descent.

Now, if other mammals, say cows, had exactly the same ERVs in the exact same positions as humans. It would be extremely unlikely for dogs to carry the three HERV-K ERVs that we know unique to humans since no other primate have them. This would be a falsification of common descent or at the very least seriously damage the model.

4.The fossil record

Phylogenetic trees indicating common descent makes specific predictions about the morphology of fossils with intermediate features because each node between any two branches predicts a common ancestor. These morphological features are explicitly specified based on an analysis of the most common derived characters (more common means higher probability that the common ancestor had them) and what transitions would have occurred at the tie. Common descent also predicts the chronological order, not just existence, of these fossils with intermediate features.

Classic cases where almost a full spectrum of fossils with few or no morphological gaps have been found includes fossils with intermediate features of dinosaur and bird, reptile and mammal, ape and human and several others.

Finding any fossil with intermediate features forbidden by common descent, such as a fossil with intermediate features form birds and mammals (the most recent common ancestor of birds and mammals where not a bird or a mammal so it could not be explained by the common ancestor having those features) would falsify common descent. There are many more examples easily deduced from the standard tree.

There are many more classes of similar evidence for common descent I could discuss, but this comment is already quite long. The important thing is that these different forms of evidence independently converging on the same conclusion of common descent.

So it is not just a matter of retrofitting facts. Common descent makes many quantitative and falsifiable predictions. Phylogenetic methodology has been supported by experimental work correctly predicting the common ancestor of lines of mice and the sequence of the common ancestor of all groups of HIV viruses. Theobald discusses this and many more important things in the article I listed above.

—–

I now understand your other points and I accept your argument, except by the caveat listed in the first paragraph of this comment and the three discussed below.

– I think this is then largely a failure of communication. For instance, in a recent article posted to the ArXiv called “The Fine-Tuning of the Universe
for Intelligent Life” you state that “We conclude that the universe is ne-tuned for the existence of life.” The problem is that the moment you use “for” in that sentence, you have unwittingly introduced a teleological principle. Perhaps you really mean to say that, as you say in your above comment, that “In the set of possible universes, the subset that permits the existence of life is very small”, in which case I understand.

There are two additional points here that are worthy of discussion.

– It should be life as we know it, because we cannot say that it is probably that no other forms of life are possible.

– It is the set of logically possible universes i.e universe that are described without resulting in a logical contradictory. This however, is presumably much larger than the set of all physically possible, but not necessarily actual, universes. There are many things that are, strictly speaking, logically possible, yet are physically improbable. I see no contradiction in the concept of a 10 ton rat, but there are biological reasons why this would be implausible. Similarly, we do not know that other configurations of physical constants are physically possible (since we cannot “do the experiment”) and even if we tentatively accept that other configurations of physical constants are physically possible, it is not necessarily the case that all of them are equally probable. So from that perspective, your statements artificially deflates probabilistic resources of critics of the teleological fine-tuning argument, which of course is not the same as the scientific conclusion that “In the set of [logically] possible universes, the subset that permits the existence of [our kind of] life is very small”.

[…] the stars and planets to form and stabilise and life to evolve, it needed to be really vast. (See Letters to Nature, where you’ll have to go about three quarters down the text to “Regarding question […]

Emil:
* I never made any claims about evolutionary biology, let alone creationist ones. “I am not in any way calling into question the truth of the hypothesis of common descent.” If you can provide a counterexample, go ahead. Where did I call into question common descent?
* The word “for” is not necessarily teleological. http://www.merriam-webster.com/dictionary/for, definition 7: “I’m a stickler for detail = I’m a stickler with respect to detail.” A more physics example is the sentence: “equation one is the equation *for* an open universe”. I very carefully defined what I meant when I claim that the universe is fine-tuned for life. It does not mean designed.
* We can do more than make claims about life as we know it. Martin Rees makes this point quite well so I’ll quote him: “Any universe hospitable to life … has to be ‘adjusted’ in a particular way. The prerequisites for any life of the kind we know about — long-lived stable stars, stable atoms such as carbon, oxygen and silicon, able to combine into complex molecules, etc — are sensitive to the physical laws and to the size, expansion rate and contents of the universe. Indeed, even for the most open-minded science ﬁction writer, ‘life’ or ‘intelligence’ requires the emergence of some generic complex structures: it can’t exist in a homogeneous universe, not in a universe containing only a few dozen particles. Many recipes would lead to stillborn universes with no atoms, no chemistry, and no planets; or to universes too short-lived or too empty to allow anything to evolve beyond sterile uniformity.”
* “we do not know that other configurations of physical constants are physically possible”. You still don’t understand the claim being made. The laws of nature define what is physically possible. Fine-tuning considers the consequences of changing the laws and constants of nature, and thus changing what is physically possible. It makes no sense whatsoever to ask whether changing physical constants is physically possible.

1. we simply do not know if our predictions, based upon our observations in this universe, would hold for different universes; it can’t be tested; any inaccuracies in our current models could have profound effects

2. we have no idea if there are “strings” between the knobs or not; the constants could be necessarily correlated and move together; seriously limiting the number of possible combinations

3. a multiverse is not necessary; you could have many cycles of this one universe and us just being in a stable configuration

Fine tuning pointing towards a designer is still, at its core, an argument from ignorance.

1. Have a close look at this plot:
This is a plot of the anisotropies of the CMB. Omega_b is the fraction of the (critical) energy density in the universe that is ordinary (baryonic) matter. We conclude from this plot that the solid line fits the data well, and thus the baryonic fraction of our universe is approximately Omega_b = 0.046.

Now, take a look at the dotted line, for Omega_b = 0.1. The way we draw that line is they way we do all theoretical physics: by writing down the equations and solving them, and then substituting in the value Omega_b = 0.1. Now, this line obviously doesn’t describe the data from our universe. So what have we done? We have described a different universe, in which the parameters of physics are different. By comparing that universe to ours, we conclude that our universe is not like that.

Now, here are your options.
a) If “we do not know if our predictions, based upon our observations in this universe, would hold for different universes”, then we cannot really draw the dotted line. We then cannot conclude that our universe does not have Omega_b = 0.1. Physics is then paralysed, unable to draw any conclusions whatsoever from observational data.
b) If, on the other hand, we (along with every other physicist) believe that we can describe different universes using our equations, then we can answer the sort of questions that fine-tuning asks, like “what would the universe be like if it were 50% more dense when it was 1 second old?”

So make your choice. If we can do physics at all, then we can make conclusions about the livability of universes with different parameters and laws.

2. True. We don’t know, but we can reasonably guess that the connecting strings must be fine-tuned. In their classic paper on fine-tuning in 1979, Carr and Rees comment that “even if all apparently anthropic coincidences could be explained [by deeper physical law], it would still be remarkable that the relationships dictated by physical theory happened also to be those propitious for life.” Similarly, Frank Wilczek has said: “Wilczek (2006b):
“It is logically possible that parameters determined uniquely by abstract theo-
retical principles just happen to exhibit all the apparent ne-tunings required to
produce, by a lucky coincidence, a universe containing complex structures. But that, I think, really strains credulity.”

3. In the literature, such a scenario is considered to be a particular type of multiverse. Multiverses could involve universes elsewhere in spacetime, so before ours, after ours, elsewhere in space, not connected at all, whatever.

“It is logically possible that parameters determined uniquely by abstract theo-
retical principles just happen to exhibit all the apparent ne-tunings required to
produce, by a lucky coincidence, a universe containing complex structures. But that, I think, really strains credulity.”

AND the let it pass without weighing in with your occasional preachy invocations of the scientific method. Selective eh?

” In other words, mind is already inherent in every electron, and the processes of human consciousness differ only in degree but not in kind from the processes of choice between quantum states which we call “chance” when they are made by electrons.”